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glibc  2.9
tcflow.c
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00001 /* Copyright (C) 1991, 1992, 1996, 1997 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <errno.h>
00020 #include <stddef.h>
00021 #include <termios.h>
00022 #include <unistd.h>
00023 
00024 #include "bsdtty.h"
00025 
00026 /* Suspend or restart transmission on FD.  */
00027 int
00028 tcflow (fd, action)
00029      int fd;
00030      int action;
00031 {
00032   switch (action)
00033     {
00034     case TCOOFF:
00035       return __ioctl (fd, TIOCSTOP, (void *) NULL);
00036     case TCOON:
00037       return __ioctl (fd, TIOCSTART, (void *) NULL);
00038 
00039     case TCIOFF:
00040     case TCION:
00041       {
00042        /* This just writes the START or STOP character with
00043           `write'.  Is there another way to do this?  */
00044        struct termios attr;
00045        unsigned char c;
00046        if (tcgetattr (fd, &attr) < 0)
00047          return -1;
00048        c = attr.c_cc[action == TCIOFF ? VSTOP : VSTART];
00049        if (c != _POSIX_VDISABLE && write (fd, &c, 1) < 1)
00050          return -1;
00051        return 0;
00052       }
00053 
00054     default:
00055       __set_errno (EINVAL);
00056       return -1;
00057     }
00058 }